The present invention relates generally to the fields of pharmaceutical compositions to be used in the treatment of cancer, autoimmune diseases and restenosis. The present invention also relates to the field of pharmaceutical preparations of anticancer agents such as paclitaxel (Taxol(trademark)) and docetaxel (Taxotere), in particular making paclitaxel water soluble by conjugating the drug to water soluble moieties.
Paclitaxel, an anti-microtubule agent extracted from the needles and bark of the Pacific yew tree, Taxus brevifolia, has shown a remarkable anti-neoplastic effect in human cancer in Phase I studies and early Phase II and III trials (Horwitz et al., 1993). This has been reported primarily in advanced ovarian and breast cancer. Significant activity has been documented in small-cell and non-small cell lung cancer, head and neck cancers, and in metastatic melanoma. However, a major difficulty in the development of paclitaxel for clinical trial use has been its insolubility in water.
Docetaxel is semisynthetically produced from 10-deacetyl baccatin III, a noncytotoxic precursor extracted from the needles of Taxus baccata and esterified with a chemically synthesized side chain (Cortes and Pazdur, 1995). Various cancer cell lines, including breast, lung, ovarian, and colorectal cancers and melanomas have been shown to be responsive to docetaxel. In clinical trials, docetaxel has been used to achieve complete or partial responses in breast, ovarian, head and neck cancers, and malignant melanoma.
Paclitaxel is typically formulated as a concentrated solution containing paclitaxel, 6 mg per milliliter of Cremophor EL (polyoxyethylated castor oil) and dehydrated alcohol (50% v/v) and must be further diluted before administration (Goldspiel, 1994). Paclitaxel (Taxol(trademark)) has shown significant activity in human cancers, including breast, ovarian, non-small cell lung, and head and neck cancers (Rowinsky and Donehower, 1995). It has also shown significant activity in patients with advanced breast cancer who had been treated with multiple chemotherapeutic agents (Foa et al., 1994). As with most chemotherapeutic agents, however, the maximum tolerated dose of paclitaxel is limited by toxicity. In humans, paclitaxel""s major toxic effect at doses of 100-250 mg/m2 is granulocytopenia (Holmes et al., 1995); symptomatic peripheral neuropathy is its principal nonhematologic toxicity (Rowinsky et al., 1993).
The amount of Cremophor EL necessary to deliver the required doses of paclitaxel is significantly higher than that administered with any other drug that is formulated in Cremophor. Several toxic effects have been attributed to Cremophor, including vasodilatation, dyspnea, and hypotension. This vehicle has also been shown to cause serious hypersensitivity in laboratory animals and humans (Weiss et al., 1990). In fact, the maximum dose of paclitaxel that can be administered to mice by i.v. bolus injection is dictated by the acute lethal toxicity of the Cremophor vehicle (Eiseman et al., 1994). In addition, Cremophor EL, a surfactant, is known to leach phthalate plasticizers such as di(2-ethylhexyl)phthalate (DEHP) from the polyvinylchloride bags and intravenous administration tubing. DEHP is known to cause hepatotoxicity in animals and is carcinogenic in rodents. This preparation of paclitaxel is also shown to form particulate matter over time and thus filtration is necessary during administration (Goldspiel, 1994). Therefore, special provisions are necessary for the preparation and administration of paclitaxel solutions to ensure safe drug delivery to patients, and these provisions inevitably lead to higher costs.
Prior attempts to obtain water soluble paclitaxel have included the preparation of prodrugs of paclitaxel by placing solubilizing moieties such as succinate, sulfonic acid, amino acids, and phosphate derivatives at the 2xe2x80x2-hydroxyl group or at the 7-hydroxyl position (Deutsch et al., 1989; Mathew et al., Zhao and Kingston, 1991, 1992; Nicolaou et al., 1993; Vyas et al., 1995, Rose et al., 1997). While some of these prodrugs possess adequate aqueous solubility, few have antitumor activity comparable to that of the parent drug (Deutsch et al., 1989; Mathew et al., 1992; Rose et al., 1997). Several of these derivatives are not suitable for i.v. injection because of their instability in aqueous solution at neutral pH. For example, Deutsch et al. (1989) report a 2xe2x80x2-succinate derivative of paclitaxel, but water solubility of the sodium salt is only about 0.1% and the triethanolamine and N-methylglucamine salts were soluble at only about 1%. In addition, amino acid esters were reported to be unstable. Similar results were reported by Mathew et al. (1992).
Recently, Nicolaou et al. (1993) reported the synthesis and in vitro biological evaluation of a novel type of prodrug termed xe2x80x9cprotaxolsxe2x80x9d. These compounds possess greater aqueous solubility and are converted to paclitaxel as the active drug through an intramolecular hydrolysis mechanism. However, no in vivo data on the antitumor activity of protaxols are yet available. Greenwald et al. reported the synthesis of highly water-soluble 2xe2x80x2 and 7-polyethylene glycol esters of paclitaxel (Greenwald et al., 1994). Using the strategy of polymer linkage, others have developed water-soluble polyethylene glycol (PEG)-conjugated paclitaxel (Li et al., 1996; Greenwald et al., 1996). Although these conjugates have excellent water solubility, their therapeutic efficacies are not better than free paclitaxel. Moreover, PEG has only two reactive functional groups at each end of its polymer chain, which effectively limit the amount of paclitaxel that PEG could carry (U.S. Pat. No. 5,362,831).
Other attempts to solve these problems have involved microencapsulation of paclitaxel in both liposomes and nanospheres (Bartoni and Boitard, 1990). The liposome formulation was reported to be as effective as free paclitaxel, however only liposome formulations containing less than 2% paclitaxel were physically stable (Sharma and Straubinger, 1994). Unfortunately, the nanosphere formulation proved to be toxic. There is still a need therefore for a water soluble paclitaxel formulation that can deliver effective amounts of paclitaxel and docetaxel without the disadvantages caused by the insolubility of the drug.
Another obstacle to the widespread use of paclitaxel is the limited resources from which paclitaxel is produced, causing paclitaxel therapy to be expensive. A course of treatment may cost several thousand dollars, for example. There is the added disadvantage that not all tumors respond to paclitaxel therapy, and this may be due to the paclitaxel not getting into the tumor. There is an immediate need, therefore, for effective formulations of paclitaxel and related drugs that are water soluble with long serum half lives for treatment of tumors, autoimmune diseases such as rheumatoid arthritis, as well as for the prevention of restenosis of vessels subject to traumas such as angioplasty and stenting.
The present invention seeks to overcome these and other drawbacks inherent in the prior art by providing compositions comprising a chemotherapeutic and/or antiangiogenic drug, such as paclitaxel, docetaxel, or other taxoid conjugated to a water soluble polymer such as a water soluble polyamino acid, or to a water soluble metal chelator. It is a further embodiment of the present invention that a composition comprising a conjugate of paclitaxel and poly-glutamic acid has surprising antitumor activity in animal models, and further that this composition is demonstrated herein to be a new species of taxane that has pharmaceutical properties different from that of paclitaxel. These compositions are shown herein to be surprisingly effective as anti-tumor agents against exemplary tumor models, and are expected to be at least as effective as paclitaxel, docetaxel, or other taxoid against any of the diseases or conditions for which taxanes or taxoids are known to be effective. The compositions of the invention provide water soluble taxoids to overcome the drawbacks associated with the insolubility of the drugs themselves, and also provide the advantages of improved efficacy and controlled release so that tumors are shown herein to be eradicated in animal models after a single intravenous administration, as well as providing a novel taxane. Poly-(l-glutamic acid) conjugated paclitaxel is shown in the examples hereinbelow to have a novel drug activity, in addition to having improved the delivery to the tumor and providing a controlled release.
The methods described herein could also be used to make water soluble polymer conjugates of other therapeutic agents, contrast agents and drugs, including paclitaxel, tamoxifen, Taxotere, etopside, teniposide, fludarabine, doxorubicin, daunomycin, emodin, 5-fluorouracil, FUDR, estradiol, camptothecin, retinoids, verapamil, epothilones cyclosporin, and other taxoids. In particular, those agents with a free hydroxyl group would be conjugated to the polymers by similar chemical reactions as described herein for paclitaxel. Such conjugation would be well within the skill of a routine practitioner of the chemical art, and as such would fall within the scope of the claimed invention. Those agents would include, but would not be limited to etopside, teniposide, camptothecin and the epothilones. As used herein, conjugated to a water soluble polymer means the covalent bonding of the drug to the polymer or chelator.
It is also understood that the water soluble conjugates of the present invention may be administered in conjunction with other drugs, including other anti-tumor or anti-cancer drugs. Such combinations are known in the art. The water soluble paclitaxel, docetaxel, or other taxoid, or in preferred embodiments the poly-(l-glutamic) acid conjugated paclitaxel (PG-TXL), of the present invention may, in certain types of treatment, be combined with a platinum drug, an antitumor agent such as doxorubicin or daunorubicin, for example, or other drugs that are used in combination with Taxol(trademark) or combined with external or internal irradiation.
Conjugation of chemotherapeutic drugs to polymers is an attractive approach to reduce systemic toxicity and improve the therapeutic index. Polymers with molecular mass larger than 30 kDa do not readily diffuse through normal capillaries and glomerular endothelium, thus sparing normal tissue from irrelevant drug-mediated toxicity (Maeda and Matsumura, 1989; Reynolds, 1995). On the other hand, it is well established that malignant tumors often have disordered capillary endothelium and greater permeability than normal tissue vasculature (Maeda and Matsumura, 1989; Fidler et al., 1987). Tumors often lack a lymphatic vasculature to remove large molecules that leak into the tumor tissue (Maeda and Matsumura, 1989). Thus, a polymer-drug conjugate that would normally remain in the vasculature may selectively leak from blood vessels into tumors, resulting in tumor accumulation of active therapeutic drug. The water soluble polymers, such as, in preferred embodiments PG-TXL, may have pharmacological properties different from non-conjugated drugs (i.e. paclitaxel). Additionally, polymer-drug conjugates may act as drug depots for sustained release, producing prolonged drug exposure to tumor cells. Finally, water soluble polymers (e.g., water soluble polyamino acids) may be used to stabilize drugs, as well as to solubilize otherwise insoluble compounds. At present, a variety of synthetic and natural polymers have been examined for their ability to enhance tumor-specific drug delivery (Kopecek, 1990, Maeda and Matsumura, 1989). However, only a few are known by the present inventors to be currently undergoing clinical evaluation, including SMANCS in Japan and HPMA-Dox in the United Kingdom (Maeda, 1991; Kopecek and Kopeckova, 1993).
In the present disclosure, a taxoid is understood to mean those compounds that include paclitaxels and docetaxel, and other chemicals that have the taxane skeleton (Cortes and Pazdur, 1995), and may be isolated from natural sources such as the Yew tree, or from cell culture, or chemically synthesized molecules, and a preferred taxane is a chemical of the general chemical formula, C47H5, NO14, including [2aR-[2axcex1,4xcex2,4xcex1xcex2,6xcex2,9xcex1(xcex1R*,xcex2S*),11xcex1,12xcex1,12axcex1,12bxcex1,]]-xcex2-(Benzoylamino)-xcex1-hydroxybenzene propanoic acid 6, 12b,bis(acetyloxy)-12-(benzoyloxy)-2a,3,4,4a,5,6,9,10,11, 12,12a,12b-dodecahydro-4,11-dihydroxy-4a,8,13,13-tetramethyl-5-oxo-7,11-methano-1H-cyclodeca[3,4]benz-[1,2-b]oxet-9-yl ester. It is understood that paclitaxel and docetaxel are each more effective than the other against certain types of tumors, and that in the practice of the present invention, those tumors that are more susceptible to a particular taxoid would be treated with that water soluble taxoid or taxane conjugate.
In those embodiments in which the paclitaxel is conjugated to a water soluble metal chelator, the composition may further comprise a chelated metal ion. The chelated metal ion of the present invention may be an ionic form of any one of aluminum, boron, calcium, chromium, cobalt, copper, dysprosium, erbium, europium, gadolinium, gallium, germanium, holmium, indium, iridium, iron, magnesium, manganese, nickel, platinum, rhenium, rubidium, ruthenium, samarium, sodium, technetium, thallium, tin, yttrium or zinc. In certain preferred embodiments, the chelated metal ion will be a radionuclide, i.e. a radioactive isotope of one of the listed metals. Preferred radionuclides include, but are not limited to 67Ga, 68Ga, 111In, 99mTc, 90Y, 114mSn and 193mPt.
Preferred water soluble chelators to be used in the practice of the present invention include, but are not limited to, diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), 1,4,7,10-tetraazacyclododecane-N,Nxe2x80x2,Nxe2x80x3,Nxe2x80x2xe2x80x3-tetraacetate (DOTA), tetraazacyclotetradecane-N,Nxe2x80x2,Nxe2x80x3Nxe2x80x3xe2x80x2-tetraacetic acid (TETA), hydroxyethylidene diphosphonate (HEDP), dimercaptosuccinic acid (DMSA), diethylenetriaminetetramethylenephosphonic acid (DTTP) and 1-(p-aminobenzyl)-DTPA, 1,6-diamino hexane-N,N,Nxe2x80x2,Nxe2x80x2-tetraacetic acid, DPDP, and ethylenebis (oxyethylenenitrilo)-tetraacetic acid, with DTPA being the most preferred. A preferred embodiment of the present invention may also be a composition comprising 111In-DTPA-paclitaxel, and Na-DTPA-paclitaxel.
In certain embodiments of the present invention, the paclitaxel, docetaxel, or other taxoid may be conjugated to a water soluble polymer, and preferably the polymer is conjugated to the 2xe2x80x2 or the 7- hydroxyl or both of the paclitaxel, docetaxel, or other taxoid. Poly-glutamic acid (PG) is one polymer that offers several advantages in the present invention. First, it contains a large number of side chain carboxyl functional groups for drug attachment. Second, PG can be readily degraded by lysosomal enzymes to its nontoxic basic component, 1-glutamic acid, d-glutamic acid and di-glutamic acid. Finally, sodium glutamate has been reported to prevent manifestations of neuropathy induced by paclitaxel, thus enabling higher doses of paclitaxel to be tolerated (Boyle et al., 1996). Preferred polymers include, but are not limited to poly(l-glutamic acid), poly(d-glutamic acid), poly(dl-glutamic acid), poly(l-aspartic acid), poly(d-aspartic acid), poly(dl-aspartic acid), poly(l-lysine), poly(d-lysine), poly(dl-lysine), copolymers of the above listed polyamino acids with polyethylene glycol, polycaprolactone, polyglycolic acid and polylactic acid, as well as poly(2-hydroxyethyl 1-glutamine), chitosan, carboxymethyl dextran, hyaluronic acid, human serum albumin and alginic acid, with poly-glutamic acids being particularly preferred. At the lower end of molecular weight, the polymers of the present invention preferably have a molecular weight of about 1,000, about 2,000, about 3,000, about 4,000, about 5,000, about 6,000, about 7,000, about 8,000, about 9,000, about 10,000, about 11,000, about 12,000, about 13,000, about 14,000, about 15,000, about 16,000, about 17,000, about 18,000, about 19,000, about 20,000, about 21,000, about 22,000, about 23,000, about 24,000, about 25,000, about 26,000, about 27,000, about 28,000, about 29,000, about 30,000, about 31,000, about 32,000, about 33,000, about 34,000, about 35,000, about 36,000, about 37,000, about 38,000, about 39,000, about 40,000, about 41,000, about 42,000, about 43,000, about 44,000, about 45,000, about 46,000, about 47,000, about 48,000, about 49,000, to about 50,000 D. At the higher end of molecular weight, the polymers of the present invention preferably have a molecular weight of about 51,000, about 52,000, about 53,000, about 54,000, about 55,000, about 56,000, about 57,000, about 58,000, about 59,000, about 60,000, about 61,000, about 62,000, about 63,000, about 64,000, about 65,000, about 66,000, about 67,000, about 68,000, about 69,000, about 70,000, about 71,000, about 72,000, about 73,000, about 74,000, about 75,000, about 76,000, about 77,000, about 78,000, about 79,000, about 80,000, about 81,000, about 82,000, about 83,000, about 84,000, about 85,000, about 86,000, about 87,000, about 88,000, about 89,000, about 90,000, about 91,000, about 92,000, about 93,000, about 94,000, about 95,000, about 96,000, about 97,000, about 98,000, about 99,000, to about 100,000 D. Within these ranges, the ranges of molecular weights for the polymers are preferably of about 5,000 to about 100,000 D, with about 20,000 to about 80,000 being preferred, or even about 25,000 to about 50,000 being more preferred.
It is a further aspect of the invention that a composition of the invention such as PG-TXL may also be conjugated to a second lipophilic or poorly soluble antitumor agent such as camptothecin, epothilone, cisplatin, melphalan, Taxotere, etoposide, teniposide, fludarabine, verapamil, or cyclosporin, for example, or even to water soluble agents such as 5 fluorouracil (5 FU) or fluorodeoxyuridine (FUDR), doxorubicin or daunomycin.
It is understood that the compositions of the present invention may be dispersed in a pharmaceutically acceptable carrier solution as described below. Such a solution would be sterile or aseptic and may include water, buffers, isotonic agents or other ingredients known to those of skill in the art that would cause no allergic or other harmful reaction when administered to an animal or human subject. Therefore, the present invention may also be described as a pharmaceutical composition comprising a chemotherapeutic or anti-cancer drug such as paclitaxel, docetaxel, or other taxoid conjugated to a high molecular weight water soluble polymer or to a chelator. The pharmaceutical composition may include polyethylene glycol, poly-glutamic acids, poly-aspartic acids, poly-lysine, or a chelator, preferably DTPA. It is also understood that a radionuclide may be used as an anti-tumor agent, or drug, and that the present pharmaceutical composition may include a therapeutic amount of a chelated radioactive isotope.
In certain embodiments, the present invention may be described as a method of determining the uptake of a chemotherapeutic drug such as paclitaxel, docetaxel, or other taxoid by tumor tissue. This method may comprise obtaining a conjugate of the drug and a metal chelator with a chelated metal ion, contacting tumor tissue with the composition and detecting the presence of the chelated metal ion in the tumor tissue. The presence of the chelated metal ion in the tumor tissue is indicative of uptake by the tumor tissue. The chelated metal ion may be a radionuclide and the detection may be scintigraphic. The tumor tissue may also be contained in an animal or a human subject and the composition would then be administered to the subject.
The present invention may also be described in certain embodiments as a method of treating cancer in a subject. This method includes obtaining a composition comprising a chemotherapeutic drug such as paclitaxel, docetaxel, or other taxoid conjugated to a water soluble polymer or chelator and dispersed in a pharmaceutically acceptable solution and administering the solution to the subject in an amount effective to treat the tumor. Preferred compositions comprise paclitaxel, docetaxel, or other taxoid conjugated to a water soluble polyamino acids, including but not limited to poly (l-aspartic acid), poly (d-aspartic acid), or poly (dl-aspartic acid), poly (l-lysine acid), poly (d-lysine acid), or poly (dl-lysine acid), and more preferably to poly (l-glutamic acid), poly (d-glutamic acid), or poly (dl-glutamic acid). The compositions of the invention are understood to be effective against any type of cancer for which the unconjugated taxoid is shown to be effective and would include, but not be limited to breast cancer, ovarian cancer, malignant melanoma, lung cancer, head and neck cancer. The compositions of the invention may also be used against gastric cancer, prostate cancer, colon cancer, leukemia, or Kaposi""s Sarcoma. As used herein the term xe2x80x9ctreatingxe2x80x9d cancer is understood as meaning any medical management of a subject having a tumor. The term would encompass any inhibition of tumor growth or metastasis, or any attempt to inhibit, slow or abrogate tumor growth or metastasis. The method includes killing a cancer cell by non-apoptotic as well as apoptotic mechanisms of cell death. The method of treating a tumor may include some prediction of the paclitaxel or docetaxel uptake in the tumor prior to administering a therapeutic amount of the drug, by methods that include but are not limited to bolus injection or infusion, as well as intraarterial, intravenous, intraperitoneal, or intratumoral administration of the drug.
This method may include any of the imaging techniques discussed above in which a paclitaxel-chelator-chelated metal is administered to a subject and detected in a tumor. This step provides a cost effective way of determining that a particular tumor would not be expected to respond to DTPA-paclitaxel therapy in those cases where the drug does not get into the tumor. It is contemplated that if an imaging technique can be used to predict the response to paclitaxel and to identify patients that are not likely to respond, great expense and crucial time may be saved for the patient. The assumption is that if there is no reasonable amount of chemotherapeutic agent deposited in the tumor, the probability of tumor response to that agent is relatively small.
In certain embodiments the present invention may be described as a method of obtaining a body image of a subject. The body image is obtained by administering an effective amount of a radioactive metal ion chelated to a paclitaxel-chelator conjugate to a subject and measuring the scintigraphic signals of the radioactive metal to obtain an image.
The present invention may also be described in certain broad aspects as a method of decreasing at least one symptom of a systemic autoimmune disease comprising administering to a subject, having a systemic autoimmune disease an effective amount of a composition comprising paclitaxel or docetaxel conjugated to polymer, with polyamino acids being preferred and poly-glutamic acid being more preferred. Of particular interest in the context of the present disclosure is the treatment of rheumatoid arthritis, which is known to respond in some cases to paclitaxel when administered in the standard Cremophor formulation (U.S. Pat. No. 5,583,153, incorporated herein by reference). As in the treatment of tumors, it is contemplated that the effectiveness of the water soluble taxoids or taxane of the present invention will not be diminished by the conjugation to a water soluble moiety. Therefore, the compositions of the present invention are expected to be as effective as paclitaxel against rheumatoid arthritis. Paclitaxel is an antiangiogenic agent. Rheumatoid arthritis creates a collection of newly formed vessels which erode the adjacent joints. It is also understood that the taxoid or taxane compositions of the present invention may be used in combination with other drugs, such as an angiogenesis inhibitor (AGM-1470) (Oliver et al., 1994), or other anti-cancer drugs, such as methotrexate.
The finding that paclitaxel also inhibits restenosis after balloon angioplasty indicates that the water soluble paclitaxels and docetaxels of the present invention will find a variety of applications beyond direct parenteral administration (WO 9625176, incorporated herein by reference). For example, it is contemplated that water soluble paclitaxel will be useful as a coating for implanted medical devices, such as tubings, shunts, catheters, artificial implants, pins, electrical implants such as pacemakers, and especially for arterial or venous stents, including balloon-expandable stents. In these embodiments it is contemplated that water soluble paclitaxel may be bound to an implantable medical device, or alternatively, the water soluble paclitaxel may be passively adsorbed to the surface of the implantable device. For example, stents may be coated with polymer-drug conjugates by dipping the stent in polymer-drug solution or spraying the stent with such a solution. Suitable materials for the implantable device should be biocompatible and nontoxic and may be chosen from the metals such as nickel-titanium alloys, steel, or biocompatible polymers, hydrogels, polyurethanes, polyethylenes, ethylenevinyl acetate copolymers, etc. In a preferred embodiment the water soluble paclitaxel, especially a PG-TXL conjugate, is coated onto a stent for insertion into an artery or vein following balloon angioplasty. The invention may be described therefore, in certain broad aspects as a method of inhibiting arterial restenosis or arterial occlusion following vascular trauma comprising administering to a subject in need thereof, a composition comprising paclitaxel or docetaxel conjugated to poly-glutamic acid or other water soluble poly-amino acids. In the practice of the method, the subject may be a coronary bypass, vascular surgery, organ transplant or coronary or any other arterial angioplasty patient, for example, and the composition may be administered directly, intravenously, or even coated on a stent to be implanted at the sight of vascular trauma.
An embodiment of the invention is, therefore, an implantable medical device, wherein the device is coated with a composition comprising paclitaxel or docetaxel conjugated to poly-glutamic acids or water soluble polyamino acids in an amount effective to inhibit smooth muscle cell proliferation. A preferred device is a stent coated with the compositions of the present invention as described herein, and in certain preferred embodiments, the stent is adapted to be used during or after balloon angioplasty and the coating is effective to inhibit restenosis.
In certain preferred embodiments, the invention may be described as a composition comprising poly-glutamic acids conjugated to the 2xe2x80x2 or 7 hydroxyl or both of paclitaxel, docetaxel, or other taxoids, or even a composition comprising water soluble polyamino acids conjugated to the 2xe2x80x2 or 7 hydroxyl or both of paclitaxel, docetaxel, or other taxoids.
As used herein, the terms xe2x80x9ca poly-glutamic acidxe2x80x9d or xe2x80x9cpoly-glutamic acidsxe2x80x9d include poly (l-glutamic acid), poly (d-glutamic acid) and poly (dl-glutamic acid), the terms xe2x80x9ca poly-aspartic acidxe2x80x9d or xe2x80x9cpoly-aspartic acidsxe2x80x9d include poly (l-aspartic acid), poly (d-aspartic acid), poly (dl-aspartic acid), the terms xe2x80x9ca poly-lysinexe2x80x9d or xe2x80x9cpoly-lysinexe2x80x9d include poly (l-lysine), poly (d-lysine), poly (dl-lysine), and the terms xe2x80x9ca water soluble polyamino acidxe2x80x9d, xe2x80x9cwater soluble polyamino acidsxe2x80x9d, or xe2x80x9cwater soluble polymer of amino acidsxe2x80x9d include, but are not limited to, poly-glutamic acid, poly-aspartic acid, poly-lysine, and amino acid chains comprising mixtures of glutamic acid, aspartic acid, and/or lysine. In certain embodiments, the terms xe2x80x9ca water soluble polyamino acidxe2x80x9d, xe2x80x9cwater soluble polyamino acidsxe2x80x9d, or xe2x80x9cwater soluble polymer of amino acidsxe2x80x9d include amino acid chains comprising combinations of glutamic acid and/or aspartic acid and/or lysine, of either d and/or l isomer conformation. In certain prefered embodiments, such a xe2x80x9cwater soluble polyamino acidxe2x80x9d contains one or more glutamic acid, aspartic acid, and/or lysine residues. Such xe2x80x9cwater soluble polyamino acidsxe2x80x9d may also comprise any natural, modified, or unusual amino acid described herein, as long as the majority of residues, i.e. greater than 50%, comprise glutamic acid and/or aspartic acid and/or lysine. In certain embodiments, a water soluble polymer of amino acids that contains more than one different type of amino acid residue is sometimes referred to herein as a xe2x80x9cco-polymerxe2x80x9d.
In certain embodiments, various substitutions of naturally occurring, unussual, or chemically modified amino acids may be made in the amino acid composition of the xe2x80x9cwater soluble polyamino acidsxe2x80x9d, and particularly in xe2x80x9cpoly-glutamic acidsxe2x80x9d, to produce a taxoid-polyamino acid conjugate of the present invention and still obtain molecules having like or otherwise desirable characteristics of solubility and/or therapeutic efficacy. A polyamino acid such as poly-glutamic acid, poly-aspartic acid, poly-lysine, or water soluble amino acids chain or polymer comprising a mixture of glutamic acid, aspartic acid, and/or lysine, may, at the lower end of the amino acid substitution range, have about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19, about 20, about 21, about 22, about 23, about 24, or about 25 or more glutamic acid, aspartic acid, or lysine, residues, respectively, substituted by any of the naturally occurring, modified, or unusual amino acids described herein. In other aspects of the invention, a polyamino acid such as poly-glutamic acid, poly-aspartic acid, poly-lysine, or a poly-amino acid chain comprising a mixture of some or all of these three amino acids may, at the lower end, have about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, to about 25% or more glutamic acid, aspartic acid, or lysine residues, respectively, substituted by any of the naturally occurring, modified, or unusual amino acids described herein.
In further aspects of the invention, a polyamino acid such as poly-glutamic acid, poly-aspartic acid, or poly-lysine may, at the high end of the amino acid substitution range, have about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, about 45%, about 46%, about 47%, about 48%, about 49%, to about 50% or so of the glutamic acid, aspartic acid, or lysine residues, respectively, substituted by any of the naturally occurring, modified, or unusual amino acids described herein, as long as the majority of residues comprise glutamic acid and/or aspartic acid and/or lysine. In amino acid substitution of the various water soluble amino acid polymers, residues with a hydrophilicity index of +1 or more are preferred.
In certain aspects of the invention, the amount of anti-tumor drug conjugated per water soluble polymer can vary. At the lower end, such a composition may comprise from about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, or about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21% about 22%, about 23%, about 24%, to about 25% (w/w) antitumor drug relative to the mass of the conjugate. At the high end, such a composition may comprise from about 26%, about 27%, about 28%, about 29%, about 30%, about 31% about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, to about 40% or more (w/w) antitumor drug relative to the mass of the conjugate. Preferred anti-tumor drugs include paclitaxel, docetaxel, or other taxoids, and preferred water soluble polymers include water soluble amino acid polymers.
In certain other aspects of the invention, the number of molecules of anti-tumor drug conjugated per molecule of water soluble polymer can vary. At the lower end, such a composition may comprise from about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19, to about 20 or more molecules of antitumor drug per molecule of water soluble polymer. At the higher end, such a composition may comprise from about 21, about 22, about 23, about 24, about 25, about 26, about 27, about 28, about 29, about 30, about 31, about 32, about 33, about 34, about 35, about 36, about 37, about 38, about 39, about 40, about 41, about 42, about 43, about 44, about 45, about 46, about 47, about 48, about 49, about 50, about 51, about 52, about 53, about 54, about 55, about 56, about 57, about 58, about 59, about 60 about 61, about 62, about 63, about 64, about 65, about 66, about 67, about 68, about 69, about 70, about 71, about 72, about 73, about 74, to about 75 or more molecules or more of antitumor drug per molecule of water soluble polymer. Preferred anti-tumor drugs include paclitaxel, docetaxel, or other taxoids, and preferred water soluble polymers include water soluble amino acid polymers. The preferred number of anti-tumor drug molecules conjugated per molecule of water soluble polymer is about 7 molecules of antitumor drug per molecule of water soluble polymer.
Water soluble amino acid polymers with various substitutions of residues conjugated to paclitaxel, docetaxel, or other taxoids are referred to as xe2x80x9cbiological functional equivalentsxe2x80x9d. These xe2x80x9cbiologically functional equivalentsxe2x80x9d are part of the definition of xe2x80x9cwater soluble polyamino acidsxe2x80x9d that are conjugated to taxoids, and may be identified by the assays described herein as well as any applicable assay that is known to those of skill in the art to measure improved aqueous solubility relative to the unconjugated taxoid or taxoids used to produce the particular water soluble amino acid polymer-taxoid composition. In other aspects of the invention, xe2x80x9cbiological functional equivalentsxe2x80x9d of water soluble amino acid-taxoid polymers may be further identified by improved anti-tumor cell activity, relative to the anti-tumor cell activity of the unconjugated taxoid or taxoids used to produce the particular water soluble amino acid polymer-taxoid composition by the assays described herein as well as any applicable assay that is known to those of skill in the art. The term xe2x80x9cbiologically functional equivalentsxe2x80x9d as used herein to describe this aspect of the invention is further described in the detailed description of the invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Also as used herein, the term xe2x80x9caxe2x80x9d is understood to include the meaning xe2x80x9cone or morexe2x80x9d. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described.